The present invention provides solutions in substantially anhydrous hydrazine of poly(hydroxymethylene), of copolymers of hydroxymethylene with up to about 30 mol percent of ethylenically unsaturated comonomers, and of mixtures thereof and a method for making filaments, i.e. fibers and film, from such solutions by introducing such solutions into a spinning bath comprising a hydrazine-miscible non-solvent for the polymer to precipitate the polymer in fiber or film form.
Vinylene carbonate, an unsaturated, cyclic 1,2-substituted ethylene derivative of the formula, ##STR1## was first prepared and polymerized by M. S. Newman and R. W. Addor (J. Am. Chem. Soc. 75, 1263 (1953) and J. Am. Chem. Soc. 77, 3758 (1955)). Poly(vinylene carbonate) is readily hydrolyzed in basic and acidic media to produce poly-(hydroxymethylene) in the form of intractible white powder. Poly(hydroxymethylene) is composed of recurring units of the formula ##STR2##
N. D. Fields and J. R. Schaefgen investigated properties of poly(hydroxymethylene) and reported that poly(hydroxymethylene) obtained by hydrolysis of poly(vinylene carbonate) in strong base or aqueous ammonia is a white powdery material soluble only in 30 percent aqueous sodium hydroxide and in sulfuric acid. They found that their high molecular weight polymer was not dissolved but only swollen by hot dimethyl sulfoxide and molten urea. Since the polymer was infusible and could not be fabricated into fibers and films using conventional methods, they made poly(hydroxymethylene) films for determination of mechanical properties of the polymer by first preparing a film of poly(vinylene carbonate) and then hydrolizing the poly(vinylene carbonate) film to obtain film of poly(hydroxymethylene) (J. Polymer Sci. 58, 533 (1962)).
Klimova et al. have reported that poly(hydroxymethylene) is soluble in hydrazine hydrate (N.sub.2 H.sub.4.H.sub.2 O) in addition to being soluble in concentrated alkali and fused urea (Zh. Prikl. Khim. 37, 1152 (1964)). Klimova et al. have further reported that poly(hydroxymethylene) is isoluble in 50 percent hydrazine, which acts only as a swelling agent, while copolymers thereof, containing 12.6 to 54.5 percent of 1,2-glycol groups, with vinyl alcohol are soluble in this medium (Zh. Prikl. Khim. 38, 2866 (1965)).
Copolymers of vinylene carbonate with ethylenically unsaturated comonomers have, for example, been disclosed in U.S. Pat. No. 2,722,525 to Price et al. and U.S. Pat. Nos. 2,847,398 and 2,847,401, both to Gluesensamp et al. Such vinylene carbonate copolymers have been hydrolyzed to form the corresponding hydroxymethylene copolymers.
Huffman et al. in U.S. Pat. No. 3,344,102 have disclosed solutions of poly(hydroxymethylene) and of copolymers of hydroxymethylene with certain ethylenically unsaturated comonomers, including vinyl acetate, vinyl chloride, vinyl fluoride, acrylonitrile and acrylamide, in aqueous solution of zinc chloride, which solutions, they stated, are useful for fiber and film formation.
It is an object of the present invention to provide solutions of poly(hydroxymethylene), including poly(hydroxymethylene) of high molecular weight and of copolymers of hydroxymethylene with ethylenically unsaturated comonomers.
It is another object of the present invention to provide a method for making fibers and film of poly(hydroxymethylene), of copolymers of hydroxymethylene with ethylenically unsaturated copolymers, and of mixtures thereof.